This invention relates generally to a spring as used in a door hinge to bias the door to a closed position as well as to securely maintain the door in one or more open positions, and is particularly directed to a vehicle door hinge such as used in automobiles and trucks.
A door hinge used in a vehicle such as an automobile or a truck generally includes a resilient spring element for controlling the position of the door. For example, the spring typically biases the door to the closed position when the door is only slightly open. In addition, the spring ensures that the door remains in one or more open positions to prevent the door from closing upon a vehicle operator or passenger upon entering or exiting the vehicle. Generally, the spring maintains the door in a stable manner in the full open position as well as in an intermediate position between the full open and closed positions. The resilient spring typically engages a portion of the hinge attached to the door for urging the door to a given position or securely maintaining the door in a desired orientation. The force exerted by the spring upon the door can be overcome by the application of sufficient force upon the door by one entering or exiting the vehicle.
Referring to FIG. 1, there is shown a perspective view of a vehicle, in this case a pickup truck, 22 incorporating a door hinge 20 in which the spring of the present invention is intended for use. The door hinge 20 pivotally couples a door 24 of the vehicle to the vehicle's frame 26. The hinge 20 allows the door 24 to be pivotally displaced about a generally vertical axis as the door is opened and closed.
Referring to FIGS. 2 and 3, there are shown two views of a door hinge 20 incorporating a prior art spring 32. The prior art spring 32 is also shown in FIG. 4. The door hinge 20 is comprised of a first hinge member 28 pivotally coupled to a second hinge member 30 by means of a pivot pin 46. The first hinge member 28 includes a plurality of apertures (not shown) therein through which first and second mounting bolts 34 and 36 are inserted for attaching the first hinge member to a vehicle frame member 26a. Each of the mounting bolts 34, 36 engages a respective threaded nut 34a, 36a attached to an inner surface of the frame member 26a. A third nut and inverted sems bolt with captive washer combination 37 is also typically provided for securely mounting the first hinge member 28 to the vehicle frame 26a. The second hinge member 30 is comprised of upper and lower portions which are coupled together by means of an intermediate hinge portion 30b. Each of the upper and lower portions of the second hinge member 30 includes one or more apertures 30a through which a mounting bolt (not shown) may be inserted for securely attaching the second hinge member to a vehicle door (also not shown for simplicity).
The upper and lower ends of the pivot pin 46 coupling the first and second hinge members 28 and 30 are each configured to engage a respective portion of the second hinge member to prevent the removal of the pivot pin from the door hinge 20. This may be accomplished by any one of a number of processes such as crimping, notching, or otherwise deforming the ends of the pivot pin 46 so as to prevent its removal from the hinge. Positioned in a spaced manner along the length of the pivot pin 46 and adjacent to respective ends thereof are upper and lower bushings 47, 48. The upper and lower bushings 47, 48 are inserted through respective apertures in the first hinge member 28 and facilitate rotation of the pivot pin 46 and the second hinge member 30 with respect to the first hinge member.
A generally S-shaped spring 32 includes a first semicircular end 32a, a linear, elongated intermediate section 32b, and a double 90.degree. bent second end 32c. The intermediate section 32b of the spring 32 is positioned within aligned notches 28a and 28b in upper and lower portions of the first hinge member 28 on a first side thereof. The distal portion of the first end 32a of the spring 32 is provided with a recess 32d for engaging a notch 28c in an upper portion of the first hinge member 28 on a second side thereof. Similarly, the distal portion of the second end 32c of spring 32 is adapted for positioning within another notch 28d in a lower portion of the first hinge member 28 on the second side thereof. Thus, the respective ends of the spring 32 are positioned within notches 28c and 28d on one side of the first hinge member 28, while the intermediate section 32b of the spring is positioned within aligned notches 28 a and 28b on the other facing side of the first hinge member. The configuration and dimensions of the spring 32 are such that the spring is maintained under tension due to torsion applied to the intermediate section 32b of the spring along the length thereof. Thus, the spring 32 must be distorted in order to mount it upon the first hinge member 28 and it is this spring distortion which maintains the spring securely in position thereon. Because of the high strength of the spring 32 used in most vehicle door hinges, a special tool is required for mounting the spring in the hinge 20.
First and second notched, or segmented, striker rollers 38 and 40 are respectively positioned upon first and second mounting pins 42 and 44 which, in turn, are mounted to and extend from a lower portion of the second hinge member 30. Positioned between the end of each of the first and second mounting pins 42, 44 and the first and second notched rollers 38, 40 is a respective corrugated washer for maintaining a notched roller in position upon a mounting pin and providing resistance to its free rotation thereon. As the vehicle door (not shown), and thus the second hinge member 30, is rotationally displaced relative to the first hinge member 28 from the closed to the full open position, the second notch roller 40 first engages the second end 32c of the spring 32 and displaces this portion of the spring. Continued opening of the door results in the second spring end 32c being positioned generally between the first and second notched rollers 38, 40 which then function to securely maintain the vehicle door in an intermediate open position. Continued outward displacement of the door causes the first notched roller 38 to engage the second spring end 32c and to deflect this portion of the spring. Further displacement of the second hinge member 30 and door combination allows the second spring end 32c to assume its original position whereupon the vehicle door is biased to the full open position. The door may be closed by reverse rotational displacement of the second hinge member 30 relative to the first hinge member 28 and the successive engagement of the first and second notched rollers 38, 40 with the second spring end 32c. As the second spring end 32c is engaged and deflected by a respective notched roller, a torque is applied to the spring 32 about the longitudinal axis of its intermediate section 32b and the spring is thus subjected to a torsional force. When the spring 32 is repeatedly subjected to this torsional force over an extended period of time, it tends to break due to structural fatigue. The prior art spring 32 generally breaks in the area of the 90.degree. bend junctures in its second end 32c after extended use.
Installation of the spring 32 requires the application of a large force thereto in order to configure it to fit the first hinge member 28 as previously described. This requires a specially designed machine or a unique tool when installation is performed by a worker. In addition, in order to ensure safety of the worker during spring installation a shield is generally positioned between the worker and the hinge. Because of the need for a special tool or machine to apply the required force to the spring and the danger involved in such an operation, failure of the spring requires replacement of the entire hinge assembly. This is an expensive repair for the vehicle owner not only because of the cost of the hinge assembly itself, but also because this removal and installation procedure requires approximately 11/2 man-hours.
The present invention avoids the aforementioned limitations of the prior art by providing a door hinge spring which is easily and safely installed and does not require complete hinge replacement upon spring failure. The door hinge spring of the present invention also affords longer operating lifetime by reducing the torsional force per unit length applied to the spring during opening and closing of the door. The biasing force applied by the spring upon the door may also be varied in several embodiments of the inventive spring in order to establish the magnitude of the force required to move the door at a desired value.